Its a mystery

Is it possible to have the low tension wires to the coils in the wrong connectors?

 

Franz, this has been addressed. -- it's the no fire on starter fluid is the mystery.

 

Yes of course l forgot about that.

 

Hey thanks for the reply. I'm going to try starter fluid with the carbs off see if a get combustion. As far as spark goes ive tried all 4 cylinders with the spark plug out and set against the engine. I haven't done it in the chamber. Will the pressure really kill the spark? I can get an inline tester if need be but if i spray starter fluid into the intake and get combustion then i know the spark is good right? As far as the engine rebuild goes I tore it down so I could change out the chain guide. It was breaking off and leaving plastic debris in my oil. I never messed with the transmission gearing at all. I looked it all over and it all looked good. No bluing or chipping or cracks that i saw. I have the manual so followed the book plus videos I've watched and read the forums. I had the cylinders honed out and new piston rings installed. The compression was checked and came back good. The numbers escape me at the moment. I just know they were within limits. Had another bike mechanic verify it. I never moved the timing plate. Ive always left it as is but the marker and TDC match up. I even gauged each cylinder to make sure they were maxed at the top and match my markings.

Thanks again for the reply. Ill check back after i try the ignition in the inlet tonight.

 

Ive done all resistance tests. They are within spec.

 

and if you get a pop, then what is the next step? extremely flammable gas 3" from a low spark will pop.
you'll still have install carbs to problem solve.

 

One of the seasoned forum guys told me this and I never believed him until it happened. Granted it was a lawnmower but I went though that carb 5 times, plug sparked fine on the head but that thing wouldn't fire to save my life. Grabbed the plug out of my power washer and it fired up. Would be unlikely you have 4 bad plugs, maybe the wrong ones though?

Good luck, keep us posted. And if it does fire then you're back to looking at the carbs etc. again.

 

If you have a colour tune you can check what is happening inside the cylinders during engine cranking. Got to be ignition if the starter fluid doesn't ignite.

 

the color tune for diagnosis is a good idea.

 

They can work together. It changes the burn time a bit, and maybe has a harder time when plugs aren't clean, but for the most part makes no difference.

 

Cheers l didn't know that.

 

The spark plugs? New or old?
One of the failure modes is having spark at atmospheric pressure, but not while in the cylinder under compression. It'd be very unlikely that all four would have that fault, but not impossible.

I'm also curious about the condition of the plug wires. Even a few pinholes in the insulation can cause a no/weak spark condition due the to spark jumping to ground at the cylinder head.

 

He might be able to see spark jumping onto the head when it's dark.

 

#1 coil wires and coil brand new. Just got 2 days ago. I will check #2 when it gets dark. Thanks

 

Yes but it takes alotxout of the equation.

 

Spark plugs are relatively new. Never ridden with them. Just used for testing. Yes I have fouled them a few times but have torched off and cleaned them to get good spark again.i have good blue spark.

 

How does color tune help if carbs aren't on? I can see using it once I know I have spark. Put the carbsxon and can get ignition enough to see the coloring. Otherwise I'm using starting fluid which will give me the wrong coloring anyway.

 

It was only to see inside the cylinder if the spark is happening on the compression stroke. Strange how you have a spark and starting fluid is not igniting.